Sectional grate for furnaces.



' LH. STRU-VE.

SECTION/XL GRATE FOR FURNACES.

APPLlCATlON-HLED JULY 12.1915.

Pdt-ented Nov. 5, 1918.

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1. H. STRUVE. SECTIONAL GRATE FOR FURNACES.

APPLICATION FILED iULY \2. 1915. f

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Patented Nov. 5,

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inhibit.

JOHN H. STRUVE, OF CHICAGO, ILLINOIS, ASSIG'i-NOR T WATER ARCH FURNACE (30., 0F CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

To all w/wmt't may concern:

Be it known that I, Jonn H. Srnovn, a citizen of the United States, and resident of Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Sectional Grates for Furnaces, of which the following is a full,

clear, and exact specification.

This invention relates to improvements in sectional grates for furnaces wherein there is a gravity feed of the fuel, and for which purpose. grate bars are inclined downwardly from the sides of the furnace and terminate at opposite sides of clinker bars, or else are inclined downwardly from the front of the furnace t the brid e wall with their several sections heretofore pivoted in such a manner that when shaken to remove ashes, the fresh fuel descends over upon the surface of the colred fuel thereon.

The prime object of my invention broadly stated, is to provide a sectional grate bar surface with means whereby the volatile matter and hydro-carbon gases from fresh coal fuel conducted upwardly through the incandescent fuel, and a correspondingly perfect combustion is produced.

More specifically stated, the object of my invention is to provide a sectional grate bar surface, the location of the pivots and form of construction of which is such that when shaken the fresh fuel will descend by gravity in contact with the grate bar surface and beneath the coked fuel. i

."inother object of my invention is to provide a sectional grate bar surface with a connecting means adapted to not only simultaneously swing the several grate bars upon ii l) their pivotal supports, but in such a manner 10 that the bottom bar shall have a greater range of movement than the top bar, and if need be, the several bars a differing range of movement increasing from the top to the bottom surface of the grate.

A further object of my invention is to provide a hanger for the shaft of the hand shaking lever, the construction of which is such that it may be secured in its operative position and removed when burnt out or 0tl1- erwise injured, for the substitution of a new hanger without disassembling any of the several other parts of a grate structure.

With these ends in View, my invention finds embodiment in certain features of nov- Specification of Letters Patent.

Patented not. a, mic.

Application filed July 1a, 1915. Serial No. taste.

elty in the construction, combination and arrangement of parts by which the said objects and certain other objects are attained, all as hereinafter fully described with reference to the accompanying drawings, and more particularly pointed out in the claims.

In said drawings:

Figure l is a transverse section taken on the line l-1 of Fig. 2 of grate bars in which my invention finds its embodiment, and which are shown in connection with a steam boiler furnace for which my invention is especially adapted.

Fig. 2 is a detail section taken on the line 2--2 of Fig. 1, and showing in elevation the grate bars at one side of the furnace.

Fig. 3 is an enlarged transverse section of one of the grate bars taken on the line of Fig. 2. i

Fig. 4 is a detail section taken on the line 4-4 of Fig. 5. i

Fig. 5 is anienlarged side elevation of the grate bar frame, the hand lever and the hanger for the shaft in their operative position, with dotted lines indicating the relative position of the several grate bars when at the extreme of their upward movement.

Fig. 6 is a detail transverse section through one sideof the furnace graphically illustrating the relative position of the fresh and coked fuel, with the grate bars in their normal position following the shaking down of the coked fuel, and- Fig. 7 is a similar view showing the rela tive position of the colced and semi-fresh fuel in their position on and relative to the grate bars at the end of their upward stroke.

Similar characters of reference indicate the same parts in the several figures of the drawings. a

While I have illustrated my invention in connection with a Dutclroven type of furnace in which the furnace therefor proj ects partly or wholly outwardly beyond the boiler 6 and the arch 7 is supported from the opposing side walls 8 and 9 of the furnace, my invention is equally well adapted for any other type of furnace in which gratebar surfaces are inclined downwardly toward each other, fromthe side walls of the furnace, or from the front wall toward the bridge Wall thereof for the purposes of a gravity feed of the coal, and which so far as my invention is concerned may be supplied by hand or by means 'of automatic stokers.

As shown in the drawing the opposing side walls of the furnace are provided with seat supports-for angle irons l0 and 11, to:

ward their upper end, supports for side bars 12 and 13', the bottom ends of which rest upon lugs 14: projecting outwardly from bars 15 and 16, supported at their front and rear-ends (see Fig. 2) by the bridge wall 17' and the front wall 18 of the furnace.

When duplex sectional grate surfaces are employed at each side of the furnace, as shown in Fig. 2, they are separated and supported at their adjacent ends respectively by additional side bars 19 and 20, and when duplex clinker bars 21 and 22 instead of a single bar are employed their opposing ends are respectively supported by bars 23 and 24:, projecting into the bridge wall and supported by the front Wall of the furnace in the same manner before described for the bars 15 and 16.

The side bars 12 and 13 are respectivelyadjacent to the bridge wall, and the front wall of the furnace, and the side bars 19 and 20 about midway between these two points, the side bars 12 and 13 being provided toward their upper edges with elongated open slots 25, and the bars 19 and 20 with perforations at intervals of their length, for forming the bearings of pivot lugs 26 at each end of three several grate bars 27 28 and 29, constituting longitudinal membersof a sectional grate surface.

' wardly above the longitudinal center of' The pivotal lugs 26 by means of which the several grate-bars are suspended from their opposing side bars are eccentric to the axis ofthebars, that is to say, are located uplength of the grate bars, with the result that when swung upwardly on their pivots from their normal position, the lower ends of thegrate bars have a substantially greater movement than their upper ends have, and whereby the bars are moved to a stepped varrangement as indicated by dotted lines in The grate bar sections 27, and 28 and 29 are respectively provided with downward projecting arms 30-31 and 32 preferably having cast therewith, bifurcated ends, between. which is confined a movable bar. 83 pivoted to said arms respectively by means of pivots 34, 35 and 36', for simultaneously swinging the several sections 27, 28 and 29 on their respective pivot bearings 26.

Inasmuch, however, as shown in the drawingsthat'the distance between pivotal supports of the grate section 27 to the pivot connecting it with the sections 33 is greater than thedistance between the same points of'support for the section 28, and this in turn greater than the distance between the points of the section 29, the angular distance through which these several bars swing successively increases for each bar from the top to the bottom of the grate surface.

As a means for actuating the grate sections for shaking down the grate, there is removably secured by means of nut bolts 37 to the outer surface of the side bars 12 and 13 a U-shaped bracket 38 projecting in a plane below the path of movement of the bar 33, and provided with an elon ated slot 39 open at its upper end, the closed end of which provides a bearing for a shaft 39 projecting outwardly beyond the front wall of the furnace, and to which is secured a hand lever 40.

Shaft 39 (see Figs. 1 and 5) has rigidly secured thereto, by means of a pin 42 passing through the shaft, a crank arm 41, the free end of which crank arm is bifurcated to receive the adjacent end of a link 43 secured thereto by means of a pivot 4-4., the other end of which link is secured well toward the end of the bar 33 by means of a pivot 45 passing diametrically through the bar 38 toward its lower end.

In operation with the lever in the position shown in Fig. 5 and at which time the surfaces of the several sections of the grate lie in the same plane, it will be seen that on moving the lever 4E0 to the left from the position shown in Fig. 5, the bar 33 through its link connection 43 with a crank arm 4-1 will simultaneously move downwardly at its upper end and upwardly at its lower end, indicated by dotted lines, with the result that the several sections of the grate will be swung on their pivots 26 upwardly from their normal plane, and gradually to the stepped arrangement indicated by dotted lines in Fig. 5, and shift the fuel accordingly into the position graphically illustrated in Fig. 7 with the result that the entire bed of fuel resting on the grate surface is bodily lifted above its normal position thereon.

For a clear understanding of the operation of the devices in which my invention finds embodiment and the results attributable thereto, it should first be noted that when the coked coal is in a highly heated incandescent condition, as indicated at 46 in Fig. 6 by the lighter shading, the rough surfaces presented by coked as compared with uncoked coal produces a more or less cohesive action between the cokcd articles and lumps, with the result that when the coke is lifted by the grate bars both when supported in contact therewith or upon the surface of an intermediate layer of uncoked coal it tends to remain in its elevated position following the receding of the grate bars therefrom.

lVhereas, on the other hand there is no such cohesionbetweenfresh coal, or that which is but slightly coked, with the reresents of coke over the adjacent surface of the into the incandescent coke, but of more im portance, that all of the gases released from the fresh and also incompletely coked fuel, are with certainty directed upwardly through thebed of incandescent coke wherein the highest degree of incandescence is thereby maintained for, and no doubt, producing the perfect combustion of all the gases, as far as may be, rising from fresh coal and also the uncoked particles of partially coked coal, D

In their operatlon the pivoting of the three sections of the grates and their simultaneous movement indicated in the drawings, provides not only for compressing the coal from its under surface upwardly but in steps forming so to speak pockets between each section somewhat shallow at their upper end, and deep at the lower edge of the grate sections, so that when the pockets are moved to their depressed position any fresh fuel thereon is free to descend by gravity from the surface of one bar to the other, and accordingly make room for fresh coal feeding by gravity from its source of supply until any unoccupied space between the surface of the grate is filled.

As a means for increasing the rapidity and amount of coal resting on and capable of descending the grate surface by gravity, and also of the fresh fuel from its source of supply, the increasing of the angular dis tance through which the several grate sections swing, beginning with the top section of the grate surface, is to be regarded as an important feature of my invention.

In other words, as shown in lFig. 7, the maximum depth of the incandescent fuel is directly over the lowest grate section 29, less over the section 28, and necessarily of minimum depth over the highestsection 27, and which in practice requires that the bottom section 29 shall move upwardly a greater distance than either of the other sections for compressing the incandescent coke above it to the greater degree required from its weight to produce an adhesion of its particles sufficient for sustaining the greater weight of the incandescent fuel in its elevated position until the grate section has moved to its normal position and the intervening space is filled either with fresh or substantially fresh fuel, as may be.

On the other hand the thickness, and therefore the weight of the incandescent coke directly over and above the upper grate section 27 being of less gravity requires accordingly less compression for sustaining it in its elevated position following the receding of that section therefrom to its normal position.

N ow, the successively increasing angular movement of the grate sections not only provides means for lifting the incandescent fuel above the grate surface, and producing by compression its adhesion suflicient to suetain such fuel in its elevated position, but a means by which it is both possible and practical to introduce a uniform thickness of fresh fuel between the incandescent coke and the grate surface if not a thickness increasing from the top to the bottom edges of the grate bars, and a body of coal sufliciently large to substantially increase the rapidity of combustion of coal in a furnace, cooling the grate bars below the temperature at which they are liable to burn,-and provide for the free and unobstructed passage of air upwardly through the grate bars, and its 'uniform distribution throughout the products of combustion rising from fresh fuel and passmg thence upwardly through a thick bed of incandescent coke.

In operation for shaking out the ashes from an incandescent bed of coke resting on the surface of the grate sections in their nor mal position, the hand lever40 may be rapidly reciprocated back and forth without stopping, but preferably with somewhat short strokes until the ashes have sifted through, following which the strokes may be increased in length for crushing cinder-s lodged between the opposing ends of the grate sections, whereupon the length of the movement of the lever is increased until the grate bars have reached the limit .of their upward movement, and the cleansed coke from compression adheres sufficiently for sustaining it in its elevated position, until coal has filled the space between its under side and the surface of the opposing grate bar.

There is substantially no limit to the thickness of the coal that may be distributed uniformly between the grate surface and the incandescent coke as will be'apparent when bearing in mind that the frictional resistance of the grate bar surface to the descending coal so little that following repeated upper movements of the grate sections the incandescent coke is lifted higher and higher with increasing thicknesses of fresh fuel on the grate bars, with the result that when the grate bars are lowered the fresh fuel resting on their surface will be accordingly loose, and so much of it as is in contact with the grate bars will descend with considerable rapidity thereon.

In conclusion it is here noted that the drawing shows (see Fig. 1) a gate 48, which may form the bottom wall of a coal chute mounted upon a pivoting rod or shaft 49 above its center of length, that is to say its center of gravity, for conducting coal from a suitable source downwardly upon and in a plane with the surface of the grate bars, and which is adapted to cut off the supply of fuel to the furnace when desired for the purpose of shaking the furnace down before i11- troducing fresh supply of coal thereto as hereinbefore described.

Having described my invention, what I claim andv desire to secure by Letters Patent is: a

1. An inclined grate comprising in combination a plurality of swinging sections, means pivotally suspending each of said sections below their upper ends and above their longitudinal centers, whereby their surfaces move by gravity to and are thereby normally maintained in the same plane.

2. An inclined grate comprising in combination a plurality of swinging sections, pivoted supports therefor, the pivots for which are located well toward but removed from their upper ends and outwardly beyond their center of gravity, and means for simultaneously swinging said sections, whereby there is imparted to them an angular movement, varying with the surface of each section, producing a bed of. fuel increasing in depth toward the bottom surface.

A furnace grate comprising in combination a plurality of swinging sections, the surfaces of which are normally in the same inclined plane extending downwardly into the furnace bearings therefor above their centers and belowtheir upper ends, the axis of which is longitudinally through each sec tion outwardly beyond the normal center of gravity thereof, and means adapted to simultaneously produce an angular movement successively varying with each section, whereby a bed of furnace fuel increasing in depth from the top'to the bottom of the grate surface upon which it rests may be lifted, and thereby subjected to a compres sion increasing in force with the depth thereof.

4. A furnace grate comprising in combination a plurality of inclined swinging sections, bearings suspending said sections respectively on longitudinal axes therethrough outwardly beyond and above their center of gravity above their longitudinal centers, a movable bar, pivots connecting said sections and bar in a plane below said bearings, the distance between which pivots and bearings substantially decreases beginning with the top section.

5. A furnace grate comprising in combination a plurality of sections, side bars therefor, provided with bearings pivotally suspending each of said sections off its center of gravity, a movable bar to which said sections are pivoted at intervals thereof, a rotatable shaft for actuating said sections, means connecting said shaft with the movable bar, U-shaped brackets detachably secured to and depending from said side bars, the closed end of which furnishes a bearing supporting the shaft in a plane substantially below the side bars for the grate, and means for operating said shaft for swinging the grate sections in stepped arrangement upwardly above their normal position.

6. An automatic side feed furnace comprising in combination clinker bars, sectional grates, fixed bars supported at their opposite ends from the bridge and front wall of the furnace providing a COlllll'lOll support for the lower end of the grates and the ends of the clinker bars adjacent thereto, angle irons detachably supporting the upper ends of the grates, bearings for each of said several grate sections, the axis of which extends longitudinally therethrough toward their upper sides, and outwardly from the center of g 'avity of said sections, movable bars pivotally connected at intervals of their length with the sections for each grate, a linkvpivoted. to said bar, a rotating shaft, a crank arm thereon pivoted to said link, a hand lever for actuating said shaft, and a detachable U-shaped hanger, the end wall of which slot supports and forms a bearing for the rotatable shaft.

7. A furnace grate comprising in combination a plurality of swinging sections, bearings therefor toward and below their upper ends pivotally suspending said sections off their center of gravity normally in the same plane, and means for simultaneously imparting to each of said sections an angular movement varying with each section and increasingly with each section progressively from the front to the rear of the furnace.

In witness whereof, I have hereuntoset my hand and affixed my seal, this th day of July, A. D. 1915.

JOHN H. STRUVE.

Witnesses M. B. ELsNER, Jno. G. ELLIOTT.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents Washington, D. G. 

